The Study on the Strength Improvement of PLA Plates by Injection Molding Based on In-Mold Heat Treatment with Induction Heating

• Main Authors: Yu-Chen Lin, 林昱辰
• Other Authors: Wen-Teng Wang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/xjve5g

碩士 === 國立虎尾科技大學 === 機械與電腦輔助工程系碩士班 === 106 === Titanium alloy & stainless steel are major materials for bone fracture fixation such as bone screws and plates in today''s medical devices. However, the fixation devices made of metal not only have the risk of metal ion release to cause human allergies, but they also need to be removed by a second surgical operation making pain and the risk of the patient’s wound infection after the bone fracture healing. The biodegradable Polylactic Acid (PLA) bone screws & bone plates have the great advantage of not needing a second operation, but their insufficient strengths make them not be widely used in the current bone fracture fixation. In the study, we use PLA as the matrix, using heat treatment to improve PLA’s crystallinity and strength. In the study, we use CAE to simulate mold’s temperature and design the heating system. Regarding ASTM F2502 “Standard Specification and Test Methods for Absorbable Plates and Screws for Internal Fixation Implants”, we design the experiments by Taguchi method to establish the orthogonal array with the 4-point bending strength to be “larger the better” quality characteristic and injection conditions, material & process parameters to be control factors. In the study, we use Material Testing Machine to test PLA’s strength. Finally, according to the experimental results of orthogonal array, the best material and process parameters of high strength of PLA bone screws & bone plates are found by ANOVA statistical analysis. It will provide a practical and important reference for the industry to develop high value-added absorbable polymer bone screws & bone plates.